From: nahi <nakahiro@...>
Date: 2012-03-18T16:50:23+09:00
Subject: [ruby-core:43409] [ruby-trunk - Feature #3429] Integer#**(large) warns "in a**b, b may be too big" and return Infinity


Issue #3429 has been updated by nahi.

Description updated
Assignee set to mrkn

mrkn, please handle this.
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Feature #3429: Integer#**(large) warns "in a**b, b may be too big" and return Infinity
https://bugs.ruby-lang.org/issues/3429#change-24722

Author: Eregon
Status: Open
Priority: Normal
Assignee: mrkn
Category: core
Target version: 2.0.0


=begin
 Hi,
 
 Trying to do
 int**some_large_number can result in
 "warning: in a**b, b may be too big"
 #=> Infinity
 By example,
 2**7830457
 
 It is not good behavior, as we can make a workaround and it works perfectly:
 # 7830457 = 2 * 37 * 105817 - 1
 n = (((2 ** 105817) ** 37) ** 2) / 2 # => ...8739992577 which is the good number
 
 I think it is not consistent to return Infinity when a correct answer can be given.
 And Integer**Integer should always return an Integer (Infinity is a Float)
 
 Also, while doing some tests about this I noticed that "bignum == Float::INFINITY" or "bignum.infinite?" hangs, while it should not, as it is always false.
 
 See the script attached for some details and a (nonsense) implementation Integer#int_pow method which show it is possible to get better results.
=end



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